Ralstonia solanacearum poses a severe threat to global agriculture due to its broad host range, high dispersal capacity, and limited chemical control options. Plant immune inducers provide an effective strategy for controlling bacterial wilt disease. This study demonstrated a natural-derived compound esculetin (ES) serves as a novel plant immune inducer against tobacco bacterial wilt. Foliar application of ES exhibits considerable control effect on tobacco bacterial wilt, with control efficacy is high as 45.41%-68.69%, significantly higher than positive control treatment-benzothiadiazole (BTH). ES activates systemic acquired resistance (SAR) by upregulating transcriptional level of pathogenesis-related (PR) genes, inducing reactive oxygen species (ROS) burst, enhancing defense-related enzyme activity and salicylic acid (SA) accumulation. Transcriptomic analyses reveal that ES induces expression of mitogen-activated protein kinase (MAPK) signaling pathways, SA biosynthesis, phenylpropanoid pathway and brassinosteroid biosynthesis pathway. Furthermore, ES confers broad-spectrum resistance against other diseases like tobacco target spot, tobacco mosaic virus (TMV), wildfire disease and tobacco black shank. The study reveals a novel plant immunity inducer ES that confers broad-spectrum resistance against R. solanacearum by activating the SA-mediated SAR pathway, which provides a sustainable application of ES on bacterial wilt and other plant diseases in the future. © 2026 Society of Chemical Industry.

New mechanistic insights into the antiviral candidate CA-P: Activation of plant redox-mediated defense and suppression of virus biosynthesis.

International trade in fresh horticultural commodities poses a high risk of emerging pests and diseases, including plant viruses. Infections of potyvirus, carlavirus, and allexivirus cause mosaic disease on garlic and potential yield loss. Potyvirus and Carlavirus have been well studied in Indonesia, but not for Allexivirus. Therefore, this study aimed to detect and identify of allexivirus species from imported garlic (consumption garlic) using reverse-transcription polymerase chain reaction (RT-PCR). Samples of garlic bulbs were collected from the plant quarantine inspection site of the regional quarantine service, North Jakarta City, DKI Jakarta Province. Individual garlic cloves were then germinated in water media. Common symptoms observed include mosaic, yellow stripes, twisted leaves, and leaf malformation. Molecular detection was done by RT-PCR using specific primers for three allexivirus species, namely Garlic virus A (GarVA), Garlic virus B (GarVB), and Garlic virus E (GarVE). Specific DNA fragments for GarVA, GarVB, and GarVE were successfully amplified from all tested samples. Nucleotide sequence analysis using SDT Matrix revealed the highest similarity of GarVA, -B, and -E with Chinese garlic isolates, i.e., 99.5%, 99.1%, and 95.0%, respectively. Further analysis revealed that Indonesian allexiviruses demonstrated a high genetic diversity and have a close genetic relationship with isolates from China. This study provides information about the occurrence of three allexiviruses in Indonesia and suggests avoiding the use of imported garlic bulbs for vegetative propagation.

Co-infection and recombination-driven emergence of begomovirus complex causing mosaic disease in muskmelon (Cucumis melo L.).

Wheat streak mosaic disease (WSMD) is the most important viral disease affecting wheat production in the US Great Plains. WSMD is caused by a single or co-infection of wheat curl mite (WCM)-transmitted wheat streak mosaic virus (WSMV), Triticum mosaic virus (TriMV), and/or High Plains wheat mosaic virus (HPWMoV). Nebraska, one of the US Great Plains states, significantly contributes to the national small grain production and utilizes cereal crops as forage and cover crops. In this study, a state-wide sampling was conducted during the 2023-2025 growing seasons across Nebraska to examine the infection dynamics of the causal agents of WSMD in winter and spring cereal crops. A total of 1624 symptomatic leaf samples were assayed with multiplex RT-PCR. In 2024, co-infection of wheat with WSMV and TriMV was more common, whereas WSMV single infections dominated in 2023. In contrast, WSMV single infections were predominant in field oats compared to WSMV-TriMV coinfection. We found a high incidence of WSMV and TriMV as single and co-infections in other cereal and forage crops: rye (80%), triticale (93%), and barley (72%). HPWMoV was found only in a few wheat samples as co-infections with WSMV or WSMV+TriMV in 2023. The P1 and CP sequences of WSMV and TriMV from different cereal hosts showed minimal sequence diversity, indicating that these viruses circulate freely among diverse cereal hosts. Our data suggest that various commercial, forage, and cover cereal crops are infected with mite-transmitted viruses in field conditions and may serve as a green bridge for the continuum of WSMD in wheat.

Yellow mosaic disease (YMD) is a major constraint in cucurbit production in India. The present study was undertaken to detect and characterise begomoviruses associated with YMD in ridge gourd (Luffa acutangula (L.) Roxb.), bitter gourd (Momordica charantia L.), ivy gourd (Coccinia grandis (L.) Voigt) and bottle gourd (Lagenaria siceraria (Molina) Standl.) from Chikmagalur, Davanagere and Shivamogga districts of Karnataka in the year 2021. Polymerase chain reaction (PCR) amplification using degenerate primers DengA/DengB and PAL1v/PAR1c confirmed the presence of begomovirus, amplifying expected fragments of ~560 bp and ~1.2–1.3 kb, respectively. Sequencing and BLASTn analysis confirm the presence of Tomato leaf curl New Delhi virus (ToLCNDV). Phylogenetic analysis showed clustering of isolates based on host and region. The ridge gourd (MZ664277), bitter gourd (MZ664278) and ivy gourd (MZ664279) isolates grouped closely, while the bottle gourd (MZ664281) formed a distinct cluster. Identity analyses confirmed 96–100 % sequence similarity with known ToLCNDV strains. The study establishes ToLCNDV as the predominant etiological agent of YMD in these cucurbits in Karnataka.

Cassava leaf diseases significantly reduce both the quantity and quality of cassava production. To address this challenge, the study developed two enhanced machine learning models—Enhanced Binary Particle Swarm Optimisation-Support Vector Machine (EBPSO-SVM) and Enhanced Reptile Search Algorithm-Support Vector Machine (ERSA-SVM)—for improved multiclass classification of cassava leaf diseases. The research utilised a dataset of 2,180 cassava leaf images from the Kaggle village repository, comprising 466 images each of cassava bacterial blight disease (CBBD), cassava brown streak disease (CBSD), cassava green mottle or mite disease (CGMD), cassava mosaic disease (CMD), and 316 images of healthy leaves. Preprocessing involved image resizing, RGB to grayscale conversion, and contrast enhancement using bi-histogram equalisation. The affected areas were segmented using the Sobel edge detection method, while Gray Level Spatial Dependence and colour moment techniques were employed for texture, shape, and colour feature extraction. Comparative experiments revealed that both the EBPSO-SVM and ERSA-SVM models achieved superior performance with an average classification accuracy of 96.42% and 95.14%, respectively, outperforming both the BPSO-SVM and RSA-SVM models, which attained an average accuracy of 95.40% and 93.86%, respectively. These findings demonstrate the effectiveness of the enhanced optimisation algorithms in overcoming dataset imbalance, premature convergence, and local optima challenges that often hinder model accuracy. In conclusion, the proposed EBPSO-SVM and ERSA-SVM models enhance classification precision and efficiency in cassava disease detection. Their adoption could facilitate early and automated identification of cassava leaf diseases, contributing to improved crop management, increased agricultural productivity, and enhanced food security in cassava-dependent regions.

Cordyceps militaris is an important medicinal and edible fungus that contains a wide range of bioactive ingredients, including cordycepin, polysaccharides, ergosterol, mannitol, proteins, and carotenoids, which collectively confer tonic, anti-fatigue, immunopotentiating, antioxidant, anti-inflammatory, and metabolic-regulating properties. Notably, the culture residue of C. militaris, which remains rich in bioactive compounds, is mostly discarded during production, resulting in resource waste and potential environmental pollution. In this study, C. militaris culture residue extract (CME) was prepared by ultrasonic extraction, and its antiviral activity was evaluated using Nicotiana benthamiana via foliar spraying. The results showed that CME treatment significantly upregulated the expression of defense-related genes PR1, PR2, and ICS1, with PR1 showing the most pronounced induction (13.20-fold before and 11.89-fold after TMV inoculation), thereby conferring strong antiviral activity. In addition, root irrigation with 10 mg/mL CME significantly increased plant height, stem diameter, dry weight, fresh weight, chlorophyll content, and carotenoid content in tomato plants. Taken together, these findings indicate that CME functions as a plant immune inducer capable of effectively suppressing tobacco viral diseases while promoting plant growth. This study not only provides a new strategy for the value-added reutilization of C. militaris culture residues but also offers a scientific basis for the green control of tobacco mosaic disease.

Cryo-electron microscopy (cryo-EM) has emerged as a powerful technique for high-resolution structural determination of macromolecules. However, accurately classifying single-particle cryo-EM images remains challenging, especially when dealing with deformed particles. In traditional 2D classification methods, clustering algorithms are used for classification. This assumption leads to some deformed particles being misclassified in 2D images, which adversely affects downstream tasks. To address this challenge, we propose a point cloud-based deformation measurement model that integrates a Variational Autoencoder (VAE) with a heuristic point cloud matching algorithm to calculate particle deformation values. This model enables the identification and removal of particles with large deformations. Our experiments on simulated and real cryo-EM datasets, including Tobacco Mosaic Virus (TMV) and mixed capsids of MS2 virions (MS2). The model achieves robust classification (F1: 0.85-0.88) while preserving 93-95% of structural details, and can effectively filter out deformed particles after 2D classification. The model identifies and removes deformed or misclassified particles to improve classification quality. It serves as a data-filtering post-processing step following 2D classification. By improving the quality of particle datasets, it enhances the reliability of subsequent analysis in cryo-EM.

Figs (Ficus carica L.) are economically important worldwide, valued for both fruit production and ornamental purposes. Due to the widespread use of vegetative propagation, diverse viruses have accumulated in fig germplasm. To date, more than 14 viruses have been described associated to fig trees, including eight members of the family Closteroviridae, although their role in the etiology of fig mosaic disease (FMD) is unclear. Characteristic symptoms of FMD include mosaic and chlorotic spots on the leaves, along with deformation of fruits and leaves. Fig mosaic virus (FMV) is the causal agent of FMD, although at least five closteroviruses have also been associated with FMD, with unclear roles. In this study, leaf samples displaying typical FMD symptoms, including yellow mosaic and mottling, were collected from a fig tree in Iowa, United States. Total RNA was extracted and subjected to high-throughput sequencing (HTS). Analysis of HTS data revealed contigs corresponding to FMV and a putative new member of the family Closteroviridae, tentatively named fig virus C (FiVC). Based on the HTS-derived sequence, we obtained the full-length genome of the putative new closterovirus using RT-PCR and RACE. The complete genome is approximately 17.8kb long with open reading frames consistent with the genomic organization of closteroviruses. Sequence comparisons and phylogenetic analysis of the RNA-dependent RNA polymerase, heat shock protein 70-like protein, and capsid protein corroborates that FiVC is a new member of the genus Closterovirus, closely related to other fig-infecting viruses. The discovery of this novel closterovirus in a symptomatic fig tree highlights the need for further studies to clarify the roles of multiple viruses in disease development.

Lateral flow immunoassays (LFAs) are widely used for on-site testing; however, their use for the rapid detection of plant viruses in the field is often limited by inconvenient sample preparation. Here, we present a new sampling method and a simplified dipstick LFA format for the detection and monitoring of cowpea chlorotic mottle virus (CCMV) as a model plant pathogen. The assay employs a monoclonal mouse antibody for capture and a poly-clonal rabbit antibody conjugated to 80 nm gold nanoparticles for detection. Conventional sample and conjugate pads are omitted, allowing the test strips to be dipped directly into wells containing plant extract and antibody-gold conjugate. No plastic casing was required, which could lead to a reduction in waste. It was shown that CCMV concentrations as low as 3.5 µg/L or 350 pg per sample could be reliably detected in 15 min. Specificity tests confirmed that other plant viruses, cowpea mosaic virus (CPMV) and tobacco mosaic virus (TMV), did not produce false-positive results. In addition, we describe a new method for on-site sampling using a manual punch and a syringe equipped with a frit. This step combines grinding the sample, extraction, filtration, and reconstitution and mixing of the antibody-gold conjugate, enabling the analysis of punched leaf disks without laboratory equipment. When applied to CCMV-infected cowpea plants, the assay revealed systemic infection before visual symptoms became apparent. This work demonstrates that simplified LFAs combined with innovative sampling techniques can provide sensitive, specific, and rapid diagnostics for crop monitoring and support early intervention strategies in agriculture.

Papaya ringspot virus watermelon strain (PRSV-W) is a member of the genus Potyvirus that infects Cucurbitaceae crops. The first occurrence of PRSV-W in Indonesia was reported in Bali in 2022. However, information regarding yield loss caused by PRSV-W infection in melon has not yet been reported. This study aimed to analyze yield loss and changes in fruit quality of melon resulting from PRSV-W infection. The research methods included individual and population level disease observations, assessment of agronomic variables and disease severity, yield loss estimation, and data analysis. Observations were conducted at the Pegok Experimental Farm, Faculty of Agriculture, Udayana University, covering an area of 1000 m². The observed plant ages ranged from 6 to 66 days after planting (dap). Mosaic disease development was observed from 18 dap until before harvest. The highest disease incidence and disease severity recorded at the end of the observation period were 58.4% and 61.8%, respectively. Actual yield loss, calculated by comparing mosaic symptomatic and asymptomatic melon plants, reached 49.45%. The most prominent quality defects were changes in fruit color and shape and fruit malformation, with values of 14.06% and 17.5%, respectively. The greatest economic loss occurred in plots with an AUDPC value of 751, resulting in a total yield loss of IDR 15,721,500. Yield loss showed strong correlations with disease incidence and disease severity, with correlation values of 95.41% and 96.19%, respectively. PRSV-W infection altered fruit skin color from yellow-orange to pale yellow with ringspot symptoms, and PRSV-W was detected in the skin tissues of infected fruits. In addition, PRSV-W infection reduced fruit sweetness to 9–12 °Brix, whereas healthy fruits exhibited sweetness levels of 14–17 °Brix.

Development and application of a sensitive and specific monoclonal antibody-based ELISA for the analysis of salicylic acid in tobacco plants.

Cassava Mosaic Disease (CMD) remains a major constraint to cassava production in Sub-Saharan Africa despite extensive promotion of management practices. This study investigates the adoption and intensity of adoption of CMD management practices among 305 cassava farmers in southern Benin, using descriptive statistics and a Tobit regression model. Results show low overall adoption: only 9.84% of farmers fully implemented all three recommended practices—use of certified disease-free cuttings, removal of infected plants, and adherence to optimal planting density. Key factors positively influencing adoption include participation in CMD-related training, disease knowledge, intercropping practices, larger farm size, and farmer age, while larger household size negatively affects adoption intensity. These findings highlight the need for integrated interventions combining farmer training, improved access to certified planting materials, intercropping promotion, and decentralized advisory services. Strengthening farmers' decision-making capacity and addressing economic constraints are critical for the sustainable management of CMD and the improvement of cassava productivity in Benin. • Adoption of CMD management practices in Benin remains low, with only 9.84% of farmers fully implementing all recommended strategies. • Participation in training and disease knowledge significantly increase adoption intensity among cassava farmers. • Certified disease-free cuttings are the least adopted practice due to high costs and limited accessibility. • Intercropping and larger farm size positively influence CMD management adoption, while larger household size negatively affects adoption intensity. • Integrated interventions combining training, input subsidies, decentralized advisory services, and whiteflies management are critical for sustainable CMD control.

Variability in growth, yield and response to cassava mosaic disease among yellow root cassava (Manihot esculenta Crantz) varieties in a rainforest agroecology of Nigeria

Cowpea is an economically important grain legume widely cultivated in Africa, Latin America, and Southeast Asia. In Southeast Asia, two of the most devastating viral diseases affecting cowpea are cowpea golden mosaic and severe leaf curl disease, both caused by Mungbean yellow mosaic India virus (MYMIV). Despite the availability of various molecular breeding strategies to manage viral infections, progress in cowpea improvement remains limited due to the lack of resistant germplasm, the absence of a reliable transformation system, and the restricted availability of efficient tools for viral gene inactivation. In this study, we employed CRISPR/Cas9-mediated genome editing technology to efficiently disrupt the common region (CR) of the single-stranded DNA-A component of legume-infecting geminiviruses, using cowpea as a test system. Transgenic cowpea plants expressing Cas9 and a guide RNA (gRNA) targeting the CR of MYMV/MYMIV were evaluated for resistance to yellow mosaic disease (YMD). Agrobacterium tumefaciens strain EHA105 carrying pXSE901B-Cas9 and CR-gRNA cassettes was used to generate the transgenic plants. PCR and Southern blot analyses confirmed the integration of transgenes into the cowpea genome. Transgenic lines in the T₁ and T₂ generations were tested for YMD resistance via agroinfiltration using MYMV and MYMIV agroinfectious clones. Accumulation of AV2 and AC2 transcripts was drastically reduced in T₂ lines, which also displayed either no or minimal mosaic symptoms. Mutation analysis of the viral genome revealed frameshift mutations near the PAM region of the targeted CR sequence, with editing frequencies of 28%, 34%, 22%, and 33% in MYMV/MYMIV-infected cowpea lines #L2, #L4, #L7, and #L11, respectively. The transgenic cowpea plants exhibited a normal phenotype and did not show any yield reduction under greenhouse conditions. To the best of our knowledge, this is the first report of transgenic cowpea plants stably expressing a geminiviral common region (CR)–targeting gRNA via the CRISPR/Cas9 system, leading to efficient editing of the MYMV/MYMIV genome and conferring durable resistance to Yellow Mosaic Disease without adversely affecting plant growth or yield. These findings demonstrate the potential of CRISPR/Cas9 as a precise and robust platform for developing virus-resistant cowpea and other legume crops.

Plant virus infections continue to pose a serious threat to global food security, causing significant agricultural and economic losses. Conventional diagnostic techniques such as enzyme-linked immunosorbent assay (ELISA), polymerase chain reaction (PCR), and next-generation sequencing (NGS) are highly sensitive and specific but are complex, require trained personnel, and involve long processing times. The convergence of nanotechnology and biosensing has revolutionized plant virus diagnostics by enabling rapid, ultrasensitive, and portable analytical platforms. This review presents an overview of recent progress in nanosensor-based detection of plant viral pathogens, emphasizing advances in diagnostic platforms, transduction mechanisms, nanomaterial technologies, and their applications in both laboratory and field conditions. Nanosensors employing gold nanoparticles, graphene, carbon nanotubes, quantum dots, and metal oxides have demonstrated excellent analytical performance for detecting major plant viruses such as tobacco mosaic virus, cucumber mosaic virus, potato virus Y, and tomato yellow leaf curl virus. Depending on their transduction mechanism—electrochemical, optical, piezoelectric, or fieldeffect transistor (FET)-based—these nanosensors exhibit femto- to attomolar sensitivity, rapid response, and seamless integration with paper-based and microfluidic systems. Their application in point-of-care (POC) and field diagnostics enables early detection and real-time monitoring of crop health. Despite these advances, challenges persist regarding reproducibility, sensor stability, environmental interference, and large-scale commercialization. Emerging technologies such as crispr–cas-integrated nanosensors, green nanomaterial synthesis, nanocomposite stabilization, and AI-driven data analytics are paving the way for robust and scalable platforms. The integration of nanosensor technology with internet of things (IoT) paradigms and precision agriculture systems heralds a new generation of intelligent, sustainable, and technology-enabled crop protection.

Identification of pesticide targets is of great significance for the development of new pesticides. The new compound GLY-15, containing a pyrimidine heterocycle and a moroxydine skeleton structure, has good anti-TMV activity, but the underlying molecular targets and mechanism of action remain elusive. Here, host malate dehydrogenase (MDH), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and tobacco mosaic virus (TMV) coat protein (CP) were identified as potential targets of GLY-15 using activity-based protein profiling (ABPP) and drug affinity responsive target stability (DARTS), and their interactions with GLY-15 were validated by microscale thermophoresis (MST) and pull-down analysis. Functional analyses demonstrate that MDH silencing significantly reduces TMV accumulation, while transient overexpression of MDH results in elevated viral infection. Meanwhile, yeast two-hybrid (Y2H), co-immunoprecipitation (Co-IP), and bimolecular fluorescence complementation (BiFC) analysis uncover that MDH interacts with CP, and their interaction is effectively inhibited by GLY-15. Site-directed mutagenesis identifies E225 as a critical residue for both GLY-15/MDH binding and MDH/CP interaction. Further investigations reveal that GLY-15 functions as an MDH inhibitor and affects its interaction with CP. Meanwhile, we showed that GLY-15 targeting MDH indicates broad antiviral activity against pepper mild mottle virus (PMMoV) and potato virus Y (PVY). This investigation systematically reveals novel insights into the anti-TMV mechanisms of GLY-15, establishing a valuable theoretical basis for antiviral target discovery and plant disease resistance breeding.

Chitosan oligosaccharide is the most extensively utilized elicitor in agricultural applications, demonstrating diverse biological activities. Its combination with other elicitors can enhance efficacy. However, challenges such as incompatibility with alkaline pesticides remain. Structural modification presents an effective strategy to address this limitation. In this study, Citral-amino-oligosaccharide Schiff base (CAOS) was prepared and found to exhibit significant anti-TMV activity. Its protective, inactivation and curative activities (at 0.9 mg/L) reached 86.32%, 57.62%, and 49.52%, respectively, significantly outperforming the positive control, chitosan oligosaccharide. Investigation into its antiviral mechanism revealed that CAOS (0.9 mg/L) induced the overexpression of related defense enzymes (SOD, CAT, POD, PAL) in tobacco, and upregulated the expression of pathogenesis-related (PR) proteins, the key reactive oxygen species (ROS) burst gene RBOHB, and the chlorophyll synthesis-related gene POR1. Hypersensitive response (HR) results indicated the appearance of hypersensitive necrotic lesions after treatment with high concentrations of CAOS. Furthermore, CAOS induced resistance in crops against plant pathogenic fungal diseases. This study is the first to report on the significant anti-TMV activity of CAOS. Its antiviral mechanism involves inducing the overexpression of disease resistance-related genes, triggering a ROS burst, activating the regulation of related defense enzymes, and consequently activating the plant's Systemic Acquired Resistance (SAR), thereby enhancing the plant's disease resistance capability. CAOS is easily prepared, highly active, has a long duration of effect, and is broad-spectrum, demonstrating potential for development as a novel plant immune activator. © 2026 Society of Chemical Industry.

Positive-strand RNA [(+)RNA] viruses induce endomembrane remodeling to form viral replication organelles (VROs), which disrupt organelle homeostasis. How hosts restore organelle homeostasis and how these responses influence viral replication remain elusive. Using beet black scorch virus (BBSV), a (+)RNA virus that replicates on the endoplasmic-reticulum (ER) and induces severe deformation of ER membranes, as a model in Nicotiana benthamiana, we demonstrated that BBSV induces ER-phagy, primarily mediated by its auxiliary replication protein p23. p23 interacts with the ER-phagy receptor NbSec62, with phenylalanine at position 48 being critical for this interaction and ER-phagy induction. Upon BBSV infection, the unfolded protein response (UPR) is triggered to promote viral replication. However, the activation of the UPR also induces NbSec62-mediated ER-phagy to suppress BBSV replication. Furthermore, NbSec62 restricts other ER-replicating (+)RNA viruses, including tobacco mosaic virus and turnip mosaic virus. Our findings reveal NbSec62 as a restriction factor that interacts with BBSV VROs to regulate the balance of viral replication and ER homeostasis, providing insights into the UPR-ER-phagy signaling network in virus-host interactions.